// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_FTP_FTP_TRANSACTION_H_
#define NET_FTP_FTP_TRANSACTION_H_

#include <stdint.h>

#include "net/base/completion_callback.h"
#include "net/base/io_buffer.h"
#include "net/base/load_states.h"
#include "net/base/net_export.h"

namespace net {

class AuthCredentials;
class FtpResponseInfo;
class FtpRequestInfo;
class BoundNetLog;

// Represents a single FTP transaction.
class NET_EXPORT_PRIVATE FtpTransaction {
public:
    // Stops any pending IO and destroys the transaction object.
    virtual ~FtpTransaction() { }

    // Starts the FTP transaction (i.e., sends the FTP request).
    //
    // Returns OK if the transaction could be started synchronously, which means
    // that the request was served from the cache (only supported for directory
    // listings).  ERR_IO_PENDING is returned to indicate that the
    // CompletionCallback will be notified once response info is available or if
    // an IO error occurs.  Any other return value indicates that the transaction
    // could not be started.
    //
    // Regardless of the return value, the caller is expected to keep the
    // request_info object alive until Destroy is called on the transaction.
    //
    // NOTE: The transaction is not responsible for deleting the callback object.
    //
    // Profiling information for the request is saved to |net_log| if non-NULL.
    virtual int Start(const FtpRequestInfo* request_info,
        const CompletionCallback& callback,
        const BoundNetLog& net_log)
        = 0;

    // Restarts the FTP transaction with authentication credentials.
    virtual int RestartWithAuth(const AuthCredentials& credentials,
        const CompletionCallback& callback)
        = 0;

    // Once response info is available for the transaction, response data may be
    // read by calling this method.
    //
    // Response data is copied into the given buffer and the number of bytes
    // copied is returned.  ERR_IO_PENDING is returned if response data is not
    // yet available.  The CompletionCallback is notified when the data copy
    // completes, and it is passed the number of bytes that were successfully
    // copied.  Or, if a read error occurs, the CompletionCallback is notified of
    // the error.  Any other negative return value indicates that the transaction
    // could not be read.
    //
    // NOTE: The transaction is not responsible for deleting the callback object.
    //
    virtual int Read(IOBuffer* buf,
        int buf_len,
        const CompletionCallback& callback)
        = 0;

    // Returns the response info for this transaction or NULL if the response
    // info is not available.
    virtual const FtpResponseInfo* GetResponseInfo() const = 0;

    // Returns the load state for this transaction.
    virtual LoadState GetLoadState() const = 0;

    // Returns the upload progress in bytes.  If there is no upload data,
    // zero will be returned.
    virtual uint64_t GetUploadProgress() const = 0;
};

} // namespace net

#endif // NET_FTP_FTP_TRANSACTION_H_
